Are you interested in building and testing your own imaging radar system? MIT Lincoln Laboratory is offering a course in the design, fabrication, and testing of a laptop-based radar sensor capable of measuring Doppler, range, and forming synthetic aperture radar (SAR) images. You do not have to be a radar engineer but it helps if you are interested in any of the following; electronics, amateur radio, physics, or electromagnetics. It is recommended that you have some familiarity with MATLAB. Teams of three will receive a radar kit and will attend a total of 5 sessions spanning topics from the fundamentals of radar to SAR imaging. Experiments will be performed each week as the radar kit is implemented. You will bring your radar kit into the field and perform additional experiments such as measuring the speed of passing cars or plotting the range of moving targets. A final SAR imaging contest will test your ability to form a SAR image of a target scene of your choice from around campus, the most detailed and most creative image wins.

Monday, November 22, 2010

Worked 68 stations during sweeps this weekend on the homebrew 20m SSB transceiver, 40 watts PEP on one band only. This was the first time i have operated sweeps. My goal was 100 but i had to do some auto repairs on sunday that got in the way while the band was open.

Worked many stations well into Sunday evening. I greatly appreciate the operators who were patient enough to receive my exchange, sometimes letting me try it numerous times through the QRM. It was fairly easy making contacts during the day but the evening was challenging.

For next year: I am considering building a large solid state power amplifier or adding 80m capability because the frequency plan should facilitate both 80 and 20.

Saturday, November 20, 2010

Last month in QST the ARRL Homebrew Challenge II was announced. I plan on competing this year. The challenge is to build a SSB/CW transceiver in 12 months that is either mono-band (10 or 6m) or dual band (both 10 and 6m).

Thursday, November 18, 2010

I recently acquired the entire MIT Radiation Laboratory Series from a friend of mine in the IEEE. This series of 28 volumes thoroughly documents to the point of providing design tables, derivations, design examples, schematics, scalable designs, the radar research conducted at the MIT Radiation Laboratory during the Second World War.

For example, one of the most famous volumes is Marcuvitz, Waveguide Handbook.

Hopefully i will be making some interesting things using this new (to my library) reference.

Abstract—A low-cost ultrawideband (UWB), 1.926-4.069 GHz, phased array radar system is developed that requires only one exciter and digital receiver that is time-division-multiplexed (TDM) across 8 receive elements and 13 transmit elements, synthesizing a fully populated 2.24 m long (λ/2element-to- element spacing) linear phased array. A 2.24 m linear phased array with a 3 GHz center frequency would require 44 antenna elements but this system requires only 21 elements and time to acquire bi-static pulses across a subset of element combinations. This radar system beamforms in the near field, where the target scene of interest is located 3-70 m down range. It utilizes digital beamforming, computed using the range migration synthetic aperture radar (SAR) algorithm. The phased array antenna is fed by transmit and receive fan-out switch matrices that are connected to a UWB LFM pulse compressed radar operating in stretch mode. The peak transmit power is 1 mW and the transmitted LFM pulses are long in time duration (2.5-10 ms), requiring the radar to transmit and receive simultaneously. It will be shown through simulation and measurement that the bi-static antenna pairs are nearly equivalent to 44 elements spacedλ/2across a linear array. This result is due to the fact that the phase center position errors relative to a uniformλ/2element spacing are negligible. This radar is capable of imaging free-space target scenes made up of objects as small as 15.24 cm tall rods and 3.2 cm tall metal nails at a 0.5 Hz rate. Applications for this radar system include short-range near-real-time imaging of unknown

Friday, November 5, 2010

After watching youtube videos of DIY or homebrew amateur radio SSB HF transceivers, and wanting to make one since i was in middle school, i became motivated to design and build this 20m SSB transceiver. I began this project in March of 2010 and have just completed it the first week of Nov 2010.

Making a radio is an art form. The looks are old-school using parts recycled from old pieces of test equipment and military surplus. Old equipment labels are on the front (covering up holes from the recycled Autographics computer chassis) warning the user 'Danger High Voltage,' and explaining that this 'modulation tester' was built under FAA contract.

ABSTRACT

A low-cost ultrawideband (UWB), 1.926–4.069 GHz, phased array radar system is developed that requires only one exciter and digital receiver that is time-division-multiplexed (TDM) across 8 receive elements and 13 transmit elements, synthesizing a fully populated 2.24 m long (λ/2 element-to-element spacing) linear phased array. A 2.24 m linear phased array with a 3 GHz center frequency would require 44 antenna elements but this system requires only 21 elements and time to acquire bi-static pulses across a subset of element combinations. This radar system beamforms in the near field, where the target scene of interest is located 3–70 m down range. It utilizes digital beamforming, computed using the range migration synthetic aperture radar (SAR) algorithm. The phased array antenna is fed by transmit and receive fan-out switch matrices that are connected to a UWB LFM pulse compressed radar operating in stretch mode. The peak transmit power is 1 mW and the transmitted LFM pulses are long in time duration (2.5–10 ms), requiring the radar to transmit and receive simultaneously. It will be shown through simulation and measurement that the bi-static antenna pairs are nearly equivalent to 44 elements spaced λ/2 across a linear array. This result is due to the fact that the phase center position errors relative to a uniform λ/2 element spacing are negligible. This radar is capable of imaging free-space target scenes made up of objects as small as 15.24 cm tall rods and 3.2 cm tall metal nails at a 0.5 Hz rate. Applications for this radar system include short-range near-real-time imaging of unknown targets through a lossy dielectric slab and radar cross section (RCS) measurements.